Ocular drug delivery systems: An overview

Figure 1 Structure of the eye.

Figure 2 Concentration-time profiles of flurbiprofen (in the aqueous humor after instillation of flurbiprofen axetil emulsion F2-F4, FB-Na eye drops and flurbiprofen axetil-oil solution in rabbits. F1 = 0.1 wt% of castor oil, 0.08 wt% of tween-80; F2 = 0.5 wt% of castor oil, 0.4 wt% of tween-80; F3 = 1.0 wt% of castor oil, 0.8 wt% of tween-80; and F4 = 2.5 wt% of castor oil, 4.0 wt% of tween-80 with 2.2 wt% and 0.1 wt% of glycerol and flurbiprofen respectively. Reproduced with permission from reference Shen et al[25]. FB: Flurbiprofen; FBA-EM: Flurbiprofen axetil emulsion.

Figure 3 Nanocarriers for ocular drug delivery.

Figure 4 Intraocular pressure in normotensive rabbit eyes after topical instillation of melatonin (MEL). ^bP < 0.01 vs melatonin; ^dP < 0.001 vs RGP-MEL1. Reproduced with permission from Musumeci et al[61]. IOP: Intraocular pressure.

Figure 5 Vitreal and retinal distribution of intravitreally administered. A: Polyethyleneimine/glycol chitosan heterogeneous nanoparticles; B: Human serum albumin/glycol chitosan heterogeneous nanoparticles; C: Human serum albumin/ hyaluronic acid heterogeneous nanoparticles 6 h post-injection. Red color = FPR-552 conjugated nanoparticles, blue color = DAPI staining of retinal cell nuclei. VH: Vitreous; RE: Retina; ILM: Inner limiting membrane; INL: Inner nuclear layer; ONL: Outer nuclear layer, respectively. All images were captured at × 10 magnification. Reproduced with permission from reference Koo et al[66].

Figure 6 Changes in intraocular pressure of rabbits eyes following administration of hydrocortisone solution and nanosuspensions produced by milling and precipitation. Reproduced with permission from reference Ali et al[70]. IOP: Intraocular pressure; Hc: Hydrocortisone; NS: Nanosuspension.

Figure 7 Acyclovir concentrations in aqueous humor after topical administration of Acyclovir solution and Acyclovir-containing liposomes. ^aP < 0.05 vs positively charged liposomes (n = 6). Reproduced with permission from reference Law et al[83]. ACV: Acyclovir.